Bituminous paving-block.



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sues flfisfififl dy l: J3 Eel/J me cmssesnmcssseescs, OF YORK, AND cHAsLss N. FORREST, OF

BRQGK JYN,.NEW YORK, ASSIGIIORS TO THE BARBER ASFELKLT ?AVING COMYi-LNY, 0F PHILADELPHIA, PEIFINSYLVANIA, A CORPURATION OF WEST VIRGINIA. I I I i svase eeeesa Specification of Letters Patent. .fieizented may Y, IQQFL ippiiestionfiiedFebruary 1?,1906. Serial 350. 351,598.

flying in size between those not passing as twenty mesh end passing an eight mesh, are toe Large t0 fill satisfactorily the intersticisl spaces or Yeids between the particles of four mesh smile, but er. the contrary force these particles apart thereby jnex'ecsing rather than diminishing v.

Now we have found. that c lmich bette mixture i secured by creating the crusher screenings in such a. View that the particles 11.4.4 whom it 7;? concern;

Be is Lmcwnthet We, {Enemies RIGEARID- sow, residing in the'bervmgh of lvienhetsen, is the ceunty of New fa'f'erk and Ste? :21" New 1' crk, and Ga-meme N. Fess'ss'r, residing in j H e berocgh cf Becolcqyc, is the ceunlly Of] her ate 0% N 3: ori Invented I l I i end ed imgamvemenss in moms f'evmgwcks, 0L which 1'0: iemng 1s sbeclficsnon.

The mvc we 1 h objec' the pi'eretained on. a. twenty or dirty mesh screen 1 A m improved 1. wng nice-K, educh, end shesc gassing e11 esqht mesh screen are,

hsvmg the eu/mvszrd features and aplerg' discarded. We then combine the particles smeiler shes. twenty mesh screen together Wit some dust as e filler, and

m the ordinary es hslt paving Ltefeye m n Iectuzed, is so pr0- internally to possess greet-er U when subjec ad. to street 15:1" c, whiie, at the time, it insuresconsmnt and e ily regulated e03: .iiens in the manw bieczss and greater unifermit-y bed p1 duct than has heretefcre ie in the art. asphalt paving b leeks heretofore men's been cempesed, to the filille of n'nety he ninety-five per centei fire stone, known crusher screenings, Passing screen. of such a size that particles srger than one-(gusset inch ,de nos intem.

portions the gi'estest density, having regard to the character *e fracture of the stone in hand, whether it be cubical, spe'lly or of other form. These preporticns usuallyeppzrcximefce sixtyfi've per cent of the eosrse and thirty-five per cent. of the fine. In this way we -secure per cent of voidgwhereas the same screen Rugs Without the advantage of the mesipulw tien develcped by our invention willv contain a, much Mlger cent ofvoids. We have "fcund further em even gl'eecer uniformity signal? the product, and sin ssphej" ether bituminous cement to bind mineral aggregate together. Fer cczwenience these 111s be secured by eliminating entirely the screenings as they ceme from the "rushes mescxisl knewn es crusher'screenings, which. have been separated mechsnicsfiy into twc 1's fer from unjfcrm in the amounter size classes, viz: materiel fine enough to pass a of individualpertieicsend possesses the usual e11 mesh screen end that cesrscr Li-um this, irregularities of any byproduct, and instead to be afterward ccm'bined into whet hes emplcying clean crushed stone, consisting heretofore been considered. suitable proper of particles which will pass a three-quarter times for making the block aggregate. fies mesh screen and be l cteined (In eight menipifla'bion does not s'ffe the grading of meshsereen. This We preferably separate eiil'ier class of Hamel-is ch remains the into two or more classes, such as those new same as it left the crusher and which, while icles passing respectively a four mesh, two ostensibly divided into swcsizes, contains a. mesh, and three quarter inch screen, dependvery lar e prdportion, fifty ereent or more, ing upon the dimensions of the block it is of psz't-ic es just 2. little ems er and just 2, H6 proposed to make. ,W'e \then recombine tie lergez than ten mesh, with. the resuit that these msterieis in definite proportions with e. iiqis not possible under the gresent practice, "fine send (ranging from ten mesh to one- Lo produce with such perticies an aggregate hundred mesh), and an 1mps1peble nunerel which will possess an appreciably greater or other powder finer than two-hundred compactness er freedom from voids or intermesh, graded according to United Stet-es stieisl s aces when ihoroughly compacted Letters Patent No. 607,884, granted (JIiflord then or inary send. The lesson for this is Richardson, July 26th, 1898. In this way, shat the pertiezes of ebeut'teggnesh size, or 1 an aggregate mey be produced cf great-er en eggregehe greet siebiiity end compsctness centslmsg but from twelve to :hliteen.

those lsrgei'. thee eight mesh in such pro-p 11H result m an aggregate of.

com actness than is possible by any other met 10d of selection heretofore practiced in the art for the selection of an aggregate For the production of asphalt paving blocks.

To practice our invention any hard crushed stone suitable "for the purpose is taken and divided by screening into particles which will be retained on a one-eighth mesh screen and pass a one-quarter mesh screen, and particles larger than one-quarter mesh but smaller than one inch mesh. Ne also take clean fine sand of the grading mentioned in Richardsons Patent No. 607,884, above referred to, and an impal able mineral or organic powder the partic es of which will pass a two-hundred mesh screen. The dry mg, storage and handling oi all of these ma terials is done in the usual manner and With aidof the machinery Well known in the art Definite proportions of these materials,

--Which are determined by Weight, are then worked together in a suitable apparatus until thoroughly n'zixed, when an amount of asphalt cement or other suitable bituminous binding material is introduced to till the remaining voids and to coat as Well the surface of each individual particle of the mineral aggregate so that when the'resultant product is compressed in the block press a homogena one block with a smooth surface is produced resembling in compactness a solid block of stone. It is apparent that the size of the lar est particles in this improved aggregate Wil be influenced as before stated by the size of the finished block it is proposed. to make, and-while it is not our intention to be limited as to the dimensions of any block, We have particular reference to the sizes "which have heretoforebeen found convenient for manufacturingand handling. For instance, in a block three inches thick, five inches Wide, and twelve inches long, it is not desirable to use stone larger than will ass a three-quarter mesh screen, and in sma ler sizes the maximum "may be reduced to that passing a one quarter inch or one half inch mesh screen It also apparent that the degree of ressure employed in molding the blocks Wil influence the appears" of the same, but in the art it is not prac able to exceed a certain pressure (and indeed the manufacturer is frequently cont ied to certain minimum. or maximum limits in this respect by the specifications of the consumer to Whom the'finished product is to be supplicdhand' with such practice We mention the. following proportions as suitable for illustrating our invention when applied to a block three inches thick, five inches Wide and twelve inches long:--st0ne, passing threeousrter inch'and retained on one-half inch mesh sci en, twenty per cent; stone, passing inch and retained on one-quarter iesli screen, twenty-eight per cent;

pas f one-quarter inch and. retained nous binding material, seven. per cent.

are

on one-eighth mesh screen, eight percent; liner material passing ten and retained on two-hundred mesh screen, twenty-five per cent; dust or 'l illcr passing two-hundred mesh screen, twelve per cent; andbituniih Of the above the sand or finer material passing ten and retained on two-hundred mesh screen (ol which twenty-live per cent is mentioned), should have the following grading or near to it as local sand supplies may perm1t:----

Passing;- 100 mesh, 17%

so 1.7% so 20% so 13% :10 10% 2o 21% v is 5% But although we have specified with exactness thfl i ferried grading according to our invention, we do not limit irseli'iesto this grading, lor siruihr advantages may be secured by other nil 'c l aggregates employing the prii'u-iple of l This princii wen ticn.

pie is biiclly this, that having regard to the maximum of stone to be employed, but assiuning about one--half or threequarter inch as the maximum, there should be a mart diminution or anprozr'rnate elimination of the sizes of in terial which lie be tween the one-eighth inch and the one twentieth inch sizes.

In the claims which follow, we use the phrase a mineral aggregate of crushed iconing This should understo 1 d to mean an aggregate such as is produced by screening; an ordinary crusher run of stone through a screen oi about three'quarters of an inch in mesh, containing all sizes of stone from an impalpable powder up to particles just passing such a mesh. li hile such screenings may vary to a certain extent according to the nature oi the stone, or the kind of crusher employed, yet there will always be present a fairly constant proportion of materials of all sizes, and it our discovery that in e nploying such crushed screenings for the purpose specified, thershould always be eliminated a considerable proportion of. the particles which lie bet-ween the eight mesh and the twenty mesh screen in order to secure the desired density of the aggregate.

Having thus described. our invention, We claim i 'l. A pay block composed of bituminous binding material and a mineral aggregate of crushed screenings running from about threequarters of an inch down to impalpablc poW- der with substantial depletion of the particles which pass a one-eighth mesh screen and are retained on a twenty mesh screen, substantial specified.

* ing block composed of a bituminous binding material, and a mineral aggregate or crushed Screenings not larger than threequ'arters of an inch in sizeand from which the excess of particles which pass a one-eighth mesh screen and are retained on a twentymesh screen are excluded, substan= tially as specified.

3. A paving block composed of a bituminous binding material, and a graded mineral aggregate composed of over 50% screened stone definitely graded from about threewhich passes a 20 mesh screen, substantially I as specified.

5. A paving block composed of a bitumi aggregate of 'which approximately 65% is nous binding material, and a graded mineral 5 between threequarters, and one-eighth of an inch in size, and the balance finer material graded substantially as follows Passing 100 mesh 1: 80 30 H 1c (I 2c 8% 1.0 5%

In testimony whereof, We have hereunto signed our names, at New York city in the State of New York this 15th day of February 1906.

onisroan RlOHARDSON. CHARLES FORREST.

Witnesses Rroni). H. BARKER, M. P. ENNIS. 

